1. Field of the Invention
This invention relates to a polyphenylene ether composition and more particularly to a polyphenylene ether composition which excels in gloss, chemical resistance, and moldability as well as in heatproofness, shock resistance, and weatherability.
2. Description of the Prior Art
The polyphenylene ether is a resin which excels in heat-proofness, chemical resistance, and mechanical and electrical properties. It nevertheless is deficient in moldability and shock resistance. Various improvements have been tried for the purpose of eliminating these drawbacks. For example, a method which resides in incorporating in the polyphenylene ether an aromatic vinyl polymer manifesting compatibility therewith has been proposed for the improvement of moldability and a method which consists in incorporating rubber in the polyphenylene ether has been offered for the improvement of shock resistance. Particularly, the incorporation of an aromatic vinyl polymer modified with rubber in the polyphenylene ether proves to be particularly advantageous, and it simultaneously improves moldability and shock resistance. The aromatic vinyl polymer modified with rubber generally contains a diene type rubber as a rubber component and, therefore, entails a problematic drawback that it quickly develops fragility on exposure to elevated temperatures or on exposure to outdoor conditions for a long time. The improvement directed to overcoming this drawback by using a copolymer produced by graft polymerizing an aromatic vinyl monomer to an ethylene-.alpha.-olefin-polyene terpolymer rubber has been proposed in Japanese Patent Publications SHO 47(1972)-43,174 and SHO 47(1972)-43,290.
Heretofore, for the production of an ethylene-.alpha.-olefin-polyene terpolymer such as, for example, the graft copolymer of an aromatic vinyl compound with an ethylene-propylene-nonconjugate diene copolymer, the method which comprises graft copolymerizing styrene, for example, by suspension polymerization, solution polymerization, or bulk polymerization, to an ethylene-propylene-nonconjugate diene copolymer has been known to the art. From the viewpoint of stability of the reaction system during the polymerization, physical properties of the produced graft copolymer, and economy of the production itself, the graft copolymerization by the process of solution polymerization predominates today.
The composition which incorporates therein the copolymer resulting from the graft polymerization of an aromatic vinyl monomer to an ethylene-.alpha.-olefin-polyene terpolymer rubber proposed in Japanese Patent Publications SHO 47(1972)-43,174 and SHO 47(1972)-43,290, however, has the disadvantage that it is inferior in gloss and chemical resistance to the system containing diene rubber.
When the graft copolymer of an ethylene-propylene-nonconjugate diene copolymer with an aromatic vinyl compound is produced by the process of solution polymerization, the produced copolymer is prevented from containing an ethylene-propylene-nonconjugate diene copolymer rubber in a high concentration and acquiring well-balanced physical properties on account of the form of polymerization. The composition to be obtained by combining the copolymer of this nature with polyphenylene ether, therefore, entails the disadvantage that it is inevitably deficient in physical properties.